Offshore hydrocarbon producing operations typically require the installation of subsea pipelines to transport the hydrocarbon products from one location to another. In many situations, installation of a subsea pipeline requires that the ends of two unconnected sections of pipeline disposed on the marine bottom must be connected by a specially fabricated spool piece which can only be fabricated by knowing the distance and angular orientation between the ends of the two unconnected sections. Heretofore, these distance and angular orientation measurements have been obtained by utilizing the services of a diver or a manned submersible vessel.
Water depths of interest to the offshore petroleum industry have now increased to the point where use of a diver or a manned submersible vessel to obtain the distance and angular orientation measurements is either prohibitively expensive or impractical. Further, in deep waters the hazards associated with manned subsea operations may be excessive. Accordingly, the need exists for a remotely operable apparatus and method which can be used to determine the distance and angular orientation between two structurally unconnected sections of a subsea pipeline without requiring manned subsea operations.